Thornton is a Canadian rower and international advocate for physical activity.
She was born in Fredericton, New Brunswick.She won a gold medal at the 2006 World Rowing Championships in the women's coxless pairs with Darcy Marquardt.
in Kinesiology and Sport Medicine from the University of Western Ontario before attending medical school at the University of Toronto, where she added an MD to her list of academic credentials.
Following medical school, she undertook a year of medical residency abroad in Switzerland and gained valuable international experience to fuel her passion for the use of physical activity for prevention and treatment of chronic disease.